Saturday, November 22, 2008

ARTICLE UPDATE - See no evil: Directing visual attention within unpleasant images modulates the electrocortical response.

Dunning JP, Hajcak G.

Psychophysiology, in press

The late positive potential (LPP) is larger for emotional than neutral stimuli, and reflects increased attention to motivationally salient stimuli. Recent studies have shown that the LPP can also be modulated by stimulus meaning and task relevance. The present studies sought to determine whether the magnitude of the LPP can be manipulated by directing attention to more or less arousing aspects within an emotional stimulus. To this end, trials included a passive viewing and directed attention portion. In both Studies 1 and 2, unpleasant compared to neutral images were associated with an increased LPP during passive viewing; additionally, directing attention to non-arousing compared to highly arousing areas of unpleasant images resulted in a decreased LPP. Results are discussed in terms of the utility of using the LPP to understand emotion-cognition interactions, especially with regard to directed visual attention as an emotion regulation strategy.

ARTICLE UPDATE - Electrophysiological correlates of decreasing and increasing emotional responses to unpleasant pictures.

Moser JS, Krompinger JW, Dietz J, Simons RF.

Psychophysiology, in press

We examined event-related brain potential (ERP) modulations during the anticipation and processing of unpleasant pictures under instructions to cognitively decrease and increase negative emotion. Instructions to decrease and increase negative emotion modulated the ERP response to unpleasant pictures in the direction of emotional intensity beginning around 400 ms and lasting several seconds. Decrease, but not increase, instructions also elicited enhanced frontal negativity associated with orienting and preparation prior to unpleasant picture onset. Last, ERP modulation by unpleasant pictures began around 300 ms, just prior to regulation effects, suggesting that appraisal of emotion occurs before emotion regulation. Together, the current findings underscore the utility of ERPs in illuminating the time course of emotion modulation and regulation that may help to refine extant theoretical models.

ARTICLE UPDATE - Stereotype threat and executive resource depletion: Examining the influence of emotion regulation.

Johns M, Inzlicht M, Schmader T.

Journal of Experimental Psychology: General, 137, 691-705

Research shows that stereotype threat reduces performance by diminishing executive resources, but less is known about the psychological processes responsible for these impairments. The authors tested the idea that targets of stereotype threat try to regulate their emotions and that this regulation depletes executive resources, resulting in underperformance. Across 4 experiments, they provide converging evidence that targets of stereotype threat spontaneously attempt to control their expression of anxiety and that such emotion regulation depletes executive resources needed to perform well on tests of cognitive ability. They also demonstrate that providing threatened individuals with a means to effectively cope with negative emotions--by reappraising the situation or the meaning of their anxiety--can restore executive resources and improve test performance. They discuss these results within the framework of an integrated process model of stereotype threat, in which affective and cognitive processes interact to undermine performance.

ARTICLE UPDATE - Validation of affective and neutral sentence content for prosodic testing.

Russ JB, Gur RC, Bilker WB.

Behavior Research Methods, 40,935-939

Conducting a study of emotional prosody often requires that one have a valid set of stimuli for assessing perceived emotion in vocal intonation. In this study, we created a list of sentences with both affective and neutral content, and then validated them against rater opinion. Participants read sentences with content that implied happiness, sadness, anger, fear, or neutrality and rated how well they could imagine each sentence being expressed in each emotion. Coefficients of variation and intraclass correlations were calculated to narrow the list to affective sentences that had high agreement and neutral sentences that had low agreement. We found that raters could easily identify most emotional content and did not ascribe any unique emotion to most neutral content. We also found differences between the intensity of male and female ratings. The final list of sentences is available on the Internet (www.med.upenn.edu/bbl/) and can be recorded for use as stimuli for prosodic studies.

ARTICLE UPDATE - Exploring the motivational brain: effects of implicit power motivation on brain activation in response to facial expressions of emoti

Schultheiss OC, Wirth MM, Waugh CE, Stanton SJ, Meier EA, Reuter-Lorenz P.

Social, Cognitive, Affective Neuroscience, in press

This study tested the hypothesis that implicit power motivation (nPower), in interaction with power incentives, influences activation of brain systems mediating motivation. Twelve individuals low (lowest quartile) and 12 individuals high (highest quartile) in nPower, as assessed per content coding of picture stories, were selected from a larger initial participant pool and participated in a functional magnetic resonance imaging study during which they viewed high-dominance (angry faces), low-dominance (surprised faces) and control stimuli (neutral faces, gray squares) under oddball-task conditions. Consistent with hypotheses, high-power participants showed stronger activation in response to emotional faces in brain structures involved in emotion and motivation (insula, dorsal striatum, orbitofrontal cortex) than low-power participants.

ARTICLE UPDATE - Rapid influence of emotional scenes on encoding of facial expressions: an ERP study.

Righart R, de Gelder B.

Social, Cognitive, Affective Neuroscience, 3, 270-278

In daily life, we perceive a person's facial reaction as part of the natural environment surrounding it. Because most studies have investigated how facial expressions are recognized by using isolated faces, it is unclear what role the context plays. Although it has been observed that the N170 for facial expressions is modulated by the emotional context, it was not clear whether individuals use context information on this stage of processing to discriminate between facial expressions. The aim of the present study was to investigate how the early stages of face processing are affected by emotional scenes when explicit categorizations of fearful and happy facial expressions are made. Emotion effects were found for the N170, with larger amplitudes for faces in fearful scenes as compared to faces in happy and neutral scenes. Critically, N170 amplitudes were significantly increased for fearful faces in fearful scenes as compared to fearful faces in happy scenes and expressed in left-occipito-temporal scalp topography differences. Our results show that the information provided by the facial expression is combined with the scene context during the early stages of face processing

Sunday, November 09, 2008

ARTICLE UPDATE - Emotional modulation of visual and motor areas by dynamic body expressions of anger.

Pichon S, de Gelder B, Grezes J.

Social Neuroscience, 3, 199-212

The ability to detect emotional meaning in others' behavior constitutes a central component of social competence. Expressions of anger in particular present salient signals that play a major role in the regulation of social interactions. Investigations of human anger signals have to date used still pictures of facial expressions but so far the neurobiological basis of bodily communication of anger remains largely unknown. Using functional magnetic resonance imaging, the present study investigated the neural bases involved in perceiving anger signals emanating from the whole body. Our study also investigates what the presence of dynamic information adds to the perception of body expressions of anger. Participants were scanned while viewing stimuli (stills or videos) of angry and neutral whole-body expressions. Whole-body expressions of anger elicit activity in regions including the amygdala and the lateral orbitofrontal cortex, which play a role in the affective evaluation of the stimuli. Importantly, the perception of dynamic body expressions of anger additionally engages the hypothalamus, the ventromedial prefrontal cortex, the temporal pole and the premotor cortex, brain regions that are coupled with autonomic reactions and motor responses related to defensive behaviors.

ARTICLE UPDATE - Effective connectivity between amygdala and orbitofrontal cortex differentiates the perception of facial expressions.

Liang X, Zebrowitz LA, Aharon I.

Social Neuroscience, in press

Emotion research is guided both by the view that emotions are points in a dimensional space, such as valence or approach-withdrawal, and by the view that emotions are discrete categories. We determined whether effective connectivity of amygdala with medial orbitofrontal cortex (MOFC) and lateral orbitofrontal cortex (LOFC) differentiates the perception of emotion faces in a manner consistent with the dimensional and/or categorical view. Greater effective connectivity from left MOFC to amygdala differentiated positive and neutral expressions from negatively valenced angry, disgust, and fear expressions. Greater effective connectivity from right LOFC to amygdala differentiated emotion expressions conducive to perceiver approach (happy, neutral, and fear) from angry expressions that elicit perceiver withdrawal. Finally, consistent with the categorical view, there were unique patterns of connectivity in response to fear, anger, and disgust, although not in response to happy expressions, which did not differ from neutral ones.

Sunday, November 02, 2008

ARTICLE UPDATE - Both predator and prey: emotional arousal in threat and reward.

Löw A, Lang PJ, Smith JC, Bradley MM.

Psychological Science, 19, 865-873

This research examined the psychophysiology of emotional arousal anticipatory to potentially aversive and highly pleasant outcomes. Human brain reactions (event-related potentials) and body reactions (heart rate, skin conductance, the probe startle reflex) were assessed along motivational gradients determined by apparent distance from sites of potential punishment or reward. A predator-prey survival context was simulated using cues that signaled possible money rewards or possible losses; the cues appeared to loom progressively closer to the viewer, until a final step when a rapid key response could ensure reward or avoid a punishing loss. The observed anticipatory response patterns of heightened vigilance and physiological mobilization are consistent with the view that the physiology of emotion is founded on action dispositions that evolved in mammals to facilitate survival by dealing with threats or capturing life-sustaining rewards.

ARTICLE UPDATE - Constructing emotion: the experience of fear as a conceptual act.

Lindquist KA, Barrett LF.

Psychological Science, 19, 898-903

This study examined the hypothesis that emotion is a psychological event constructed from the more basic elements of core affect and conceptual knowledge. Participants were primed with conceptual knowledge of fear, conceptual knowledge of anger, or a neutral prime and then proceeded through an affect-induction procedure designed to induce unpleasant, high-arousal affect or a neutral affective state. As predicted, only those individuals for whom conceptual knowledge of fear had been primed experienced unpleasant core affect as evidence that the world was threatening. This study provides the first experimental support for the hypothesis that people experience world-focused emotion when they conceptualize their core affective state using accessible knowledge about emotion.

ARTICLE UPDATE - How does negative emotion cause false memories?

Brainerd CJ, Stein LM, Silveira RA, Rohenkohl G, Reyna VF.

Psychological Science, 19, 919-925

Remembering negative events can stimulate high levels of false memory, relative to remembering neutral events. In experiments in which the emotional valence of encoded materials was manipulated with their arousal levels controlled, valence produced a continuum of memory falsification. Falsification was highest for negative materials, intermediate for neutral materials, and lowest for positive materials. Conjoint-recognition analysis produced a simple process-level explanation: As one progresses from positive to neutral to negative valence, false memory increases because (a) the perceived meaning resemblance between false and true items increases and (b) subjects are less able to use verbatim memories of true items to suppress errors.

ARTICLE UPDATE - Attention, emotion, and deactivation of default activity in inferior medial prefrontal cortex.

Geday J, Gjedde A.

Brain and Cognition, in press

Attention deactivates the inferior medial prefrontal cortex (IMPC), but it is uncertain if emotions can attenuate this deactivation. To test the extent to which common emotions interfere with attention, we measured changes of a blood flow index of brain activity in key areas of the IMPC with positron emission tomography (PET) of labeled water (H(2)(15)O) uptake in brain of 14 healthy subjects. The subjects performed either a less demanding or a more demanding task of attention while they watched neutral and emotive images of people in realistic indoor or outdoor situations. In the less demanding task, subjects used the index finger to press any key when a new image appeared. In the more demanding task, subjects chose the index or middle finger to press separate keys for outdoor and indoor scenes. Compared to the less demanding task, in a global search of all gray matter, the more demanding significantly lowered blood flow (rCBF) in left IMPC, left and right insula, and right amygdala, and significantly raised blood flow in motor cortex and right precuneus. Restricted searches of rCBF changes by emotion, at coordinates of significant effect in previous studies of the medial prefrontal and temporal cortices, revealed significant activation in the fusiform gyrus, independently of the task. In contrast, we found no effect of emotional content in the IMPC, where emotions failed to override the effect of the task. The results are consistent with a role of the IMPC in the selection among competitive inputs from multiple brain regions, as predicted by the theory of a default mode of brain function. The absent emotional interference with the deactivation of the default state suggests that the inferior prefrontal cortex continued to serve the attention rather than submit to the distraction.